The present invention relates to a storage and transportation container for loose cartridges, the shell portion of which container is comprised of a plastic material.
Loose cartridges are typically powder cartridges packed in cotton-cloth bags. Wooden or cardboard packages have usually been used for such cartridges. A problem related to such packages is a relatively low strength and a poor ability to remain dry in connection with a long-term storage. Attempts have been made to improve the moisture-resistance properties, e.g. by means of plastic coatings, but plastic coatings cause the occurrence of static electricity and its charging in the container, which causes a risk of explosion.
Loose-cartridge containers are also known, in which the case is made of thermoplastic by means of bottle, blow or rotation molding methods. However, these methods cannot provide sufficiently rigid walled tube structures, and it has not been possible to prevent the charging of static electricity in applications concerned.
Loose-cartridge containers are also known, in which attempts have been made to solve the problems caused by static electricity. One such application is described in GB application No. 2 101 559, wherein the container is comprised of fabrics or cloths containing plastic. In accordance with this publication, the charging of static electricity is prevented by placing conductive wires in the cloth fabric. These wires are connected to a suitable conductive member, e.g. a carrier handle, located outside the container, via which member the electric charges may be discharged. However, the container according to the GB publication cannot provide a sufficient strength, and furthermore, the static-electricity discharging system described is cumbersome and expensive to realize.
GB patent publication 1 277 550 also describes such a container in which the case portion is comprised of a case made of glass-fiber reinforced polyester resin. The container is mainly intended for hydrocarbon fluids, but it is also suitable for fine-grained solid material. In this publication, static electricity is collected in a metal wire structure embedded in the inner surface of the container, which structure conducts static electricity to an earthing point located outside the container.
GB patent publication 1 277 550 mainly relates to the preparation of the material to be used for the preparation of the container. The actual container is formed of this material by cutting suitable parts and by fixing and seaming the parts together. The preparation method is thus cumbersome and expensive.